1. Field of the Invention
The present invention relates to an image processing apparatus and an image processing method, and more particularly, to an encoding apparatus capable of encoding image data delivered in a digital terrestrial broadcast, for example.
2. Description of the Related Art
In the past, there was developed a wireless transmission technology wirelessly transmitting HD (High Definition) video data to a display apparatus, such as a wall-hung television, located distantly. As a transmission method using this wireless transmission technology, millimeter waves using the 60 GHz band, IEEE 802.11n (wireless LAN (Local Area Network)) using the 5 GHz band, UWB (Ultra Wide band), etc. are exemplified.
In the wireless transmission technology, HD video data is compressed by encoding before transmission. In the wireless transmission technology, it is preferable that delay of the transmission of the HD video data to the display of the HD video data on a display apparatus is reduced as much as possible to realize the real-time display of a broadcast program in a digital terrestrial broadcast.
For example, in an encoding method of changing I, P, and B pictures in each picture, the encoding amount of I picture is larger than that of the other pictures. For this reason, when this encoding method is applied to the wireless transmission technology, it is necessary to buffer data in a GOP (Group Of Picture) unit with a uniform encoding amount, and thus the delay is also increased.
In order to solve this problem, there has been suggested an image processing apparatus which encodes and transmits the HD video data by an intra slice method using MPEG (Moving Picture Experts Group)-2, as shown in FIG. 1 (for example, see Japanese Unexamined Patent Application Publication No. 11-205803).
In the intra slice method using MPEG-2, pictures include I picture regions I_MB subjected to intra encoding and P picture regions P_MB subjected to forward prediction encoding. In the intra slice method, an I picture region (hereinafter, referred to as a refresh line) RL formed by a predetermined MB line number for one picture emerges. The refresh lines RL are sequentially shown in a deviated manner and are shown in all of the pictures in a period T.
Therefore, the intra slice method can reduce the delay from the transmission of the HD video data to the display of the HD video data on a display apparatus as small as possible, since the encoding amount of each picture can be made uniform.